<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
</head>
<body>
<div id="app">
  <!--<h2 :style="{key(属性名): value(属性值)}">{{message}}</h2>-->
  <!--'50px'必须加上单引号，否则是当作一个变量去解析-->
  <h2 :style="{fontSize: '50px'}">{{message}}</h2>
  <!--finalSize当成一个变量使用-->
  <h2 :style="{fontSize: finalSize, backgroundColor: finalColor}">{{message}}</h2>
  <h2 :style="getStyles()">{{message}}</h2>
</div>

<script src="../js/vue.js"></script>
<script>
  const app = new Vue({
    el: '#app',
    data: {
      message: '你好',
      finalSize: '100px',
      finalColor: 'red'
    },
    methods: {
      getStyles: function() {
        return {fontSize: this.finalSize, backgroundColor: this.finalColor};
      }
    }
  });
</script>
</body>
</html>